ibmvnic: Do not replenish RX buffers after every polling loop

Reduce the amount of time spent replenishing RX buffers by only doing
so once available buffers has fallen under a certain threshold, in this
case half of the total number of buffers, or if the polling loop exits
before the packets processed is less than its budget. Non-exhaustion of
NAPI budget implies lower incoming packet pressure, allowing the leeway
to refill the buffers in preparation for any impending burst.

Signed-off-by: Dwip N. Banerjee <dnbanerg@us.ibm.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index 96df6d8..9fe43ab 100644 (file)
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -2537,7 +2537,10 @@ restart_poll:
                frames_processed++;
        }
 
-       if (adapter->state != VNIC_CLOSING)
+       if (adapter->state != VNIC_CLOSING &&
+           ((atomic_read(&adapter->rx_pool[scrq_num].available) <
+             adapter->req_rx_add_entries_per_subcrq / 2) ||
+             frames_processed < budget))
                replenish_rx_pool(adapter, &adapter->rx_pool[scrq_num]);
        if (frames_processed < budget) {
                if (napi_complete_done(napi, frames_processed)) {